An interventional study of Vagal nerve stimulation through deep exhalation exercise and Vagal nerve stimulation through ear electrical stimulation in Widspread Chronic Pain, Fibromyalgia, sponsored by University of North Georgia. Not yet recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-07-23.
Sponsored by University of North Georgia · Not applicable, Interventional, and Treatment
The goal of this clinical trial is to examine the effect of vagus nerve stimulation (VNS) on chronic, widespread pain in adults. The study will also evaluate which method of VNS-electrical ear stimulation or deep exhalation breathing-has a more significant impact on pain intensity, quality of life, and emotional well-being.
The main questions it aims to answer are:
Does vagus nerve stimulation reduce pain intensity in individuals with chronic, widespread pain?
Which intervention-electrical ear stimulation or deep exhalation breathing-provides a greater improvement in autonomic function, emotional status, and quality of life?
Researchers will compare two active interventions-electrical ear stimulation and deep exhalation breathing-to a no-treatment control group to determine relative effectiveness on pain and related outcomes.
Participants will:
Be randomly assigned to one of three groups:
Complete four questionnaires to assess pain, emotional state, and quality of life.
Undergo physiological assessments including heart rate variability, neck muscle tissue flexibility (via MyotonPro), and pressure pain sensitivity (via pressure algometer), both before and after the 2-week period.
Participation includes two in-person sessions (approximately 1 hour each) and daily home practice (for intervention groups) lasting 40-60 minutes per day for two weeks. The study involves minimal risk, and no compensation is provided. Participation is voluntary, and confidentiality will be strictly maintained.
Detailed Description:
Study Overview:
This randomized controlled clinical trial investigates the effects of two forms of non-invasive vagus nerve stimulation (VNS) on chronic widespread pain (CWP). The study is designed to explore whether stimulating the vagus nerve through auricular electrical stimulation (AES) or deep forced exhalation (DFE) improves pain, muscle stiffness, and functional status in individuals with CWP.
Vagal nerve stimulation (VNS) has been associated with modulation of the autonomic nervous system, leading to downstream effects on inflammation, pain perception, and emotional regulation. This study compares the effectiveness of these two intervention methods with a control group that receives no treatment during the study period.
Research Questions:
Hypotheses:
Study Procedures and Assessments:
Participants will be randomly assigned to one of three groups:
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Heart Rate Variability (HRV):
Assessed using the Polar H10 chest strap sensor.
Muscle Stiffness and Tissue Compliance:
Measured using the MyotonPRO device on the upper trapezius. • Equipment preparation: The MyotonPRO is calibrated before each session.
Pain Pressure Threshold (PPT):
Assessed with a handheld analog pressure algometer at three locations: mid trapezius, L5 lumbar paraspinal, and gastrocnemius-soleus junction.
Pain Level:
Measured using the Visual Analog Scale (VAS), a 10 cm line from "no pain" to "worst pain imaginable."
Quality of Life:
Measured with the Quality of Life Scale (QOLS), covering physical, emotional, and social domains.
Emotional State:
Assessed using the Positive and Negative Affect Schedule (PANAS), which rates 10 positive and 10 negative emotions.
Evaluated using the Patient Health Questionnaire-9 (PHQ-9), a 9-item tool commonly used in research and clinical practice.
Intervention Protocols:
Auricular Electrical Stimulation (AES):
o Waveform: Biphasic rectangular
o Pulse width: 200-300 µs
o Frequency: 20 Hz
o Intensity: Starting at 0.1 mA, increased until tingling is comfortable but not painful
o Duration: 20 minutes per session, twice daily for 2 weeks
Deep Forced Exhalation (DFE):
Participants undergo all pre- and post-study assessments but receive no intervention during the two-week period. They are debriefed afterward and may opt to receive either treatment following data collection.
Safety Considerations:
Potential AES risks include local irritation, tingling, warmth, lightheadedness, or bradycardia. All participants are screened and monitored during the first session. Instructions emphasize safe positioning, hydration, and gradual adjustment of intensity. Participants are advised to stop the session and contact the research team if they feel unwell.
DFE carries low risk, with occasional lightheadedness or fatigue reported. This is minimized by recommending seated practice and gradual breath intensity. Participants are asked to rest after each session.
Expected Benefits:
Participants may experience decreased pain sensitivity, improved autonomic regulation, better emotional well-being, and improved quality of life. These outcomes are not guaranteed, and no monetary compensation is offered for participation.
Contact Information:
Dr. Reza Nourbakhsh Email: Reza.nourbakhsh@ung.edu Phone: 706-864-1766
1,336 studies on the registry are indexed under Fibromyalgia; 265 are open to participants now.
This study's planned enrollment of 100 is above the median of 60 across 1,034 interventional studies indexed under Fibromyalgia.
Browse Fibromyalgia studies →University of North Georgia is the lead sponsor of 5 studies on the registry; 1 is open to participants now.
Counted across the registry records on this site, refreshed daily.
Adults 18 years of age or older
Diagnosed by a healthcare provider with chronic widespread pain or fibromyalgia
Exclusion Criteria:
Cardiovascular disorders: Such as arrhythmia (irregular heartbeat), heart failure, coronary artery disease, or history of heart surgery
Neurological disorders: Including epilepsy, Parkinson's disease, multiple sclerosis, neuropathy, or seizures
Endocrine disorders: Such as uncontrolled diabetes, thyroid disease (hypothyroidism or hyperthyroidism), or adrenal disorders
Gastrointestinal disorders: Including inflammatory bowel disease (Crohn's disease, ulcerative colitis), irritable bowel syndrome, or chronic acid reflux (GERD)
Respiratory disorders: Such as asthma, chronic bronchitis, emphysema, or sleep apnea
Vestibular disorders: Including Meniere's disease, benign paroxysmal positional vertigo (BPPV), or any condition causing balance problems
History of concussion or traumatic brain injury
Frequent dizziness or vertigo: History of unexplained or recurring episodes
Chronic or recurrent headaches: Including migraines, tension-type headaches, or cluster headaches
Ear problems: History of ear infections, hearing loss, tinnitus (ringing in the ears), or ear surgeries
Throat problems: History of chronic sore throat, difficulty swallowing (dysphagia), or throat surgery
Herniation: History of any type of herniation such as spinal disc herniation, inguinal (groin) hernia, or abdominal hernia
Skin sensitivity to electrical stimulation: Known allergic reaction, rash, or irritation from electrode pads or electrical devices applied to the skin
Vagal nerve stimulation will be performed through deep exhalation exercise, performed once every hour during the waking hours each day.
Other: Vagal nerve stimulation through deep exhalation exercise
Vagal nerve stimulation will be performed through applying low frequency electrical stimulation to the external ear lobe for 20 minutes twice a day.
Other: Vagal nerve stimulation through ear electrical stimulation
Participants in this group will not receive any treatment for vagal nerve stimulation.
Other: No intervention (observational study)
Deep Exhalation Treatment: Participants will receive a set of standard balloons to use for deep exhalation. They will sit in a comfortable position, take a deep breath in and blow their breath continuously out into the balloon. They repeat the deep exhalation process for a total of 4 consecutive breaths. They perform this breathing exercise once every hour during waking hours each day.
Ear Electrical Stimulation Treatment: Participants will receive a small electrical stimulator and electrode set to be applied to their left ear. The investigators will train the participants to use the device safely and effectively. Once they are comfortable with the procedure, they will perform the procedure at home for 20 minutes twice daily.
The no intervention group will not receive treatment immediately after their baseline assessments, they will be scheduled for another visit after two weeks, then a new set of baseline measurements will be recorded as the post intervention data.
Pain Intensity
Pain intensity will be assessed using the Visual Analog Scale (VAS), a 10 cm horizontal line anchored by "no pain" and "worst imaginable pain." Participants mark their current level of pain on the line, which is measured in centimeters (cm).
Time frame: From enrollment to the end of treatment at 2 weeks
Muscle stiffness
Muscle stiffness, defined as the resistance of the tissue to an external force, will be measured in the upper trapezius using the MyotonPro device. Stiffness reflects the biomechanical integrity of muscle tissue. Unit of Measure: Newtons per meter (N/m)
Time frame: Frome enrollment to the end of treatment at 8 weeks
Pressure Pain Threshold - Trapezius muscle
Pressure pain threshold (PPT) at the mid-belly of the upper trapezius will be assessed using a calibrated analog pressure algometer. PPT is defined as the minimum force required to elicit pain and reflects mechanical pain sensitivity. Unit of Measure: Kilograms per square centimeter (kg/cm²).
Time frame: From enrollment to the end of treatment period at 2 weeks
SDNN (Standard Deviation of NN intervals)
SDNN will be used to assess overall heart rate variability, reflecting both sympathetic and parasympathetic nervous system activity over a 10-minute resting period. Unit of Measure: milliseconds (ms).
Time frame: From enrollment to the end of treatment at 2 weeks
Mechanical Stress Relaxation Time
Mechanical Stress Relaxation Time, defined as the time required for tissue to return to its original state following a mechanical impulse, will be measured using the MyotonPro device. This parameter reflects the viscoelastic properties of skeletal muscle. Unit of Measure: milliseconds (ms).
Time frame: From enrollment to the end of treatment at 8 weeks
Muscle Oscillation Frequency
Frequency, representing the natural oscillation frequency of muscle tissue in response to a brief mechanical impulse, will be measured using the MyotonPro device. It reflects the intrinsic muscle tone and biomechanical behavior of the tissue. Unit of Measure: Hertz (Hz).
Time frame: From enrollment to the end of treatment at 8 weeks.
Pressure Pain Threshold - Lumbar Paraspinal Muscles
PPT at the lumbar paraspinal region (L5 level) will be measured using an analog pressure algometer to assess localized pain sensitivity. Unit of measurement: Kilograms per square centimeter (kg/cm²)
Time frame: From enrollment to the end of treatment at 8 weeks
Pressure Pain Threshold - Calf Muscles
PPT at the junction of the gastrocnemius and soleus muscles in the calf will be measured using a pressure algometer to evaluate distal pain sensitivity. Unit of Measure: Kilograms per square centimeter (kg/cm²)
Time frame: From enrollment to the end of treatment at 8 weeks
Muscle Elasticity (Logarithmic Decrement)
Elasticity, measured as logarithmic decrement, describes the ability of muscle tissue to return to its original shape after deformation. It will be measured using the MyotonPro on the upper trapezius. Lower values indicate greater elasticity. Unit of Measure: Unitless (logarithmic decrement)
Time frame: From enrollment to the end of treatment at 8 weeks
RMSSD (Root Mean Square of Successive Differences)
RMSSD will be used as a marker of short-term parasympathetic activity. Unit of Measure: milliseconds (ms).
Time frame: Baseline, after 2 weeks and after 8 weeks
SDANN (Standard Deviation of Average NN intervals)
SDANN will be used to evaluate longer-term components of heart rate variability associated with sympathetic activity. Unit of Measure: milliseconds (ms)
Time frame: Baseline, after 2 weeks, and after 8 weeks
LF Power (Low Frequency Power)
LF Power will be analyzed to assess contributions from both sympathetic and parasympathetic nervous systems in frequency domain. Unit of Measure: milliseconds² (ms²).
Time frame: Baseline, after 2 weeks and after 8 weeks
HF Power (High Frequency Power)
HF Power will be measured to evaluate parasympathetic (vagal) nervous system activity. Unit of Measure: milliseconds² (ms²).
Time frame: Baseline, after 2 weeks and after 8 weeks
LF/HF Ratio
LF/HF ratio will be used as a marker of autonomic balance, indicating the relative influence of sympathetic to parasympathetic tone. Unit of Measure: Ratio (unitless).
Time frame: Baseline, after 2 weeks and after 8 weeks
VLF Power (Very Low Frequency Power)
VLF Power will be measured to assess longer-term regulatory systems, including thermoregulation and hormonal factors. Unit of Measure: milliseconds² (ms²).
Time frame: Baseline, after 2 weeks and after 8 weeks
ULF Power (Ultra Low Frequency Power)
ULF Power will be assessed to capture circadian and ultradian influences on autonomic regulation. Unit of Measure: milliseconds² (ms²).
Time frame: Baseline, after 2 weeks and after 8 weeks
Quality of Life (Quality of Life Scale - QOLS)
The Quality of Life Scale (QOLS) will be used to evaluate participants' perceived well-being and life satisfaction across physical, social, and personal domains. The scale includes 16 items scored from 1 to 7, with total scores ranging from 16 to 112. Unit of Measure: Total score (range: 16-112). Higher scores indicate better quality of life.
Time frame: From enrollment to the end of treatment period at 2 weeks.
Positive Affect Score (PANAS)
The Positive and Negative Affect Schedule (PANAS) will be used to assess emotional state. The positive affect subscale contains 10 items, each rated from 1 (very slightly or not at all) to 5 (extremely), yielding scores from 10 to 50. Unit of Measure: Total score (range: 10-50). Higher scores indicate a higher level of positive emotional state.
Time frame: From enrollment to the end of treatment period at 2 weeks
Depression Severity (Patient Health Questionnaire-9)
The Patient Health Questionnaire-9 (PHQ-9) is a 9-item self-report scale measuring depression symptom severity. Each item is rated from 0 (not at all) to 3 (nearly every day), with a total score ranging from 0 to 27. Unit of Measure: Total score (range: 0-27). Higher scores indicate more severe depressive symptoms.
Time frame: From enrollment to the of treatment period at 2 weeks
Negative Affect Score (Positive and Negative Affect Schedule - PANAS)
The PANAS negative affect subscale consists of 10 items, each scored from 1 to 5, with a total score ranging from 10 to 50. This subscale measures levels of distress and negative emotionality. Unit of Measure: Total score (range: 10-50). Higher scores indicate greater negative emotional states.
Time frame: From enrollment to the end of treatment at 8 weeks
Muscle Creep/Compliance
Creep (or compliance), representing the viscoelastic behavior of muscle over time, will be assessed using the MyotonPro device. This parameter reflects the ability of muscle tissue to deform gradually under sustained stress. Unit of Measure: Deborah number (or dimensionless unit, based on device output)
Time frame: From enrollment to the end of treatment at 8 weeks
Plan to share: Yes — IPD that underlie results in a publication
Supporting information: Study protocol, Sap, Icf
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